Double-walled flexible dispenser sump connection system

ABSTRACT

A double-walled flexible dispenser sump connection system prevents fuel leaks into a dispenser sump located below a fuel dispenser. An inner flexible connector and an outer flexible connector are configured such that the dispenser sump connection system may be installed on newly constructed fuel delivery systems or be retrofitted onto existing fuel delivery systems in order to bring them into compliance with recently environmental regulations.

TECHNICAL FIELD

This invention relates generally to fuel dispenser sumps used in gas stations and in similar applications, and more particularly to a double-walled flexible dispenser sump connection system that provides a safeguard against leaks from dispenser sumps located beneath the gasoline dispensers.

BACKGROUND AND SUMMARY OF THE INVENTION

State environmental and energy agencies require strict compliance with laws and regulations regarding fuel storage and conveyance, in particular regarding containment of fuel within the pipes and other components beneath the ground surface at gas stations. Piping systems for conveying the fuel between the underground tanks and dispensers must be pressurized and vacuum sealed to detect and contain leaks therein.

Referring to FIG. 1, there is shown a common dispenser sump connection system 10 below a dispenser 12 at a gas station. Fuel is conveyed from a tank 14 through a primary inner pipe 16, traditionally two inches in diameter, into a dispenser sump 18 below the fuel dispenser 12. Once inside the dispenser sump 18 the inner pipe 16 continues through an elbow joint 20 to a connecting inner pipe 22, which couples to a shear valve 24 located at the bottom of the dispenser 12. The shear valve 24 prevents fuel spills or leaks in the event that the dispenser 12 is displaced from the dispenser sump 18.

A secondary outer pipe 26, traditionally three inches in diameter, encloses the inner pipe 16 from the tank 14 to the dispenser sump 18. The outer pipe 26 prevents fuel from entering into and contaminating the groundsoil and/or the atmosphere. The interstitial space between the outer pipe 26 and the inner pipe 16 is either pressurized or vacuum sealed to provide additional protection against leaks.

Although the outer pipe 26 contains any leaks between the tank 12 and the dispenser sump 18, the outer pipe 26 terminates into a boot at the dispenser sump 18, leaving the inner pipe 16 is exposed inside the dispenser sump 18. Therefore, there are no safeguards to detect or contain leaks that occur inside the dispenser sump 18, which can result in leaks into the groundsoil surrounding the dispenser sump and/or into the atmosphere. Recently, regulations have been passed in several states such as California which require safeguards be installed to prevent leaks from dispenser sumps. Currently the approved safeguards require retrofitting the existing dispenser sump 18 with the equivalent of an outer sump around the dispenser sump within the space between the outer and inner sump being either pressurized or vacuum sealed, or replacing the existing dispenser sump with a double-walled pressurized sump. The cost to install the outer sump or replace the existing sump costs approximately $ 2,000 minimum per dispenser. Considering that most gas stations have multiple dispensers, the cost to retrofit the existing sumps to bring them into compliance can be substantial.

The present invention comprises a dispenser sump connection system which overcomes the foregoing and other difficulties which have long since characterized the prior art. In accordance with the broader aspects of the invention, an outer and inner flexible connector system provides protection against fuel leakage from the dispenser sump. The inner flexible connector connects the primary inner pipe to the shear valve. The outer flexible connector completely encloses the inner flexible connector from the sump wall to the shear valve. The interstitial space between the outer flexible connector and the inner flexible connector is pressurized and/or be vacuum sealed thereby preventing any fuel leakage into the dispenser sump.

The outer and inner flexible connector system can be retrofitted inside existing dispenser sumps at a minimal cost per dispenser. The present invention provides the high level of protection against leakage required by state environmental agencies and eliminates the need for installing an outer sump or retrofitting with a double-walled sump.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention may be had by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings, wherein:

FIG. 1 is a sectional view illustrating a prior art fuel delivery and dispenser sump connection system;

FIG. 2 is a sectional view of the double-walled flexible dispenser sump connection system of the present invention;

FIG. 3 is an exploded perspective view of the dispenser sump connection system shown in FIG. 2;

FIG. 4 is a sectional view of the dispenser sump connection system shown in FIG. 2.

DETAILED DESCRIPTION

Referring now to the Drawings, and particularly to FIGS. 2, 3, and 4 thereof, there is shown the dispenser sump connection system 30 of the present invention. An inner flexible connector 32 is connected to the inner pipe 16 for completing the conveyance of fuel to the dispenser 12. An outer flexible connector 34 is installed over and completely encloses the inner flexible connector 32. The lower end of the outer flexible connector 34 is connected in fluid communication with the outer pipe 26. The upper end of the outer flexible connector 34 is connected to the shear valve 24 thereby completing the containment of any leaks from either the inner pipe 16 and the inner flexible connector 32. The interstitial space between the outer flexible connector 34 and the inner flexible connector 32 is either pressurized or vacuum sealed thereby preventing any fuel leakage into the dispenser sump 18. The flexible connectors 32 and 34 used in conjunction with the present invention are described in detail in currently pending U.S. patent applications Ser. No. 10/689279 filed Oct. 20, 2003; Ser. No. 10/736,416 filed Dec. 15, 2003; and Ser. No.______ filed Jan. 21, 2005 (Attorney Docket Number 200625-1003).

In the embodiment shown in FIGS. 2 through 4, the inner flexible connector 32 couples to the inner pipe 16 through an elbow joint 36 comprising an inner elbow joint 38 secured to the distal end of the inner pipe and an outer containment clamshell 40, which glues over the inner elbow joint 38 to contain any leaks that may occur therefrom. The dispenser sump connection system 30 of the present invention may be also be secured directly to the inner and outer pipes 16 and 26, or by other connection means known to those skilled in the art and suitable for use in fuel and hazardous material delivery systems.

FIGS. 3 is an exploded view and FIG. 4 is a sectional view of the dispenser sump connection system 30. The inner flexible connector 32 threadedly secures into the inner elbow joint 38, thereby completing the connection of the inner flexible connector 32 to the inner pipe 16. The top of the inner flexible connector 32 has male threads for threadedly securing the inner flexible connector into the shear valve 24. The outer flexible connector 34 installs over the inner flexible connector 32 and is connected to the elbow joint 36 by a lower connection ring 42, which extends around the end of the inner elbow joint 38. The outer containment clamshell 40 when glued over the inner elbow joint 38 covers and thereby contains the connection of the lower connection ring 42 to the inner elbow joint 38.

The lower end of the outer flexible connector 34 is secured to the lower connection ring 42 by a first hinged circular clamp 44 having a threaded locking mechanism 46. A gasket 48 is mounted between the outer flexible connector 34 and lower connection ring 42. Wedge shaped surfaces on the outer flexible connector 34 and on the lower connection ring 42 and corresponding shapes on the inner surfaces of the circular clamp 44, combined with the gasket 48, cause the outer flexible connector 34 and the lower connection ring 42 to form a compression seal as the threaded locking mechanism 46 is tightened.

The upper end of the outer flexible connector 34 is connected to the shear valve 24 by an upper connection ring 50. The outer flexible connector 34 is secured to the upper connection ring 50 by a second hinged circular clamp 44 having a threaded locking mechanism 46. A gasket 48 is positioned between the outer flexible connector 34 and upper connection ring 50. Wedge shaped surfaces on the outer flexible connector 34 and on the upper connection ring 50 and corresponding shapes on the inner surfaces of the circular clamp 44, combined with the gasket 48, cause the outer flexible connector 34 and the upper connection ring 50 to form a compression seal as the threaded locking mechanism 46 is tightened. The upper connection ring 50 comprises female threads for threadedly securing an outer housing 52 of the shear valve 24 thereinto.

Near the upper end of the outer flexible connector 34 is an orifice 54 which facilitates either vacuum sealing or pressurization of the interstitial space between the inner flexible connector 32 and the outer flexible connector 34.

The lower connection ring 42, the upper connection ring 50, and the hinged circular clamps 44 may be formed from stainless steel, bronze, brass, monel, other metals, various polymeric materials, and other materials that will not be adversely affected by the fluid that will flow through the inner and outer flexible connectors 32 and 34. The inner elbow joint 38 and the outer elbow joint 40 are commercially available parts used in conjunction with fuel delivery systems and other hazardous material delivery systems.

Although preferred embodiments of the invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention. 

1. For use in conjunction with a fuel supply system comprising a piping system having an inner pipe and an outer pipe, the inner pipe for conveying fuel between a tank and a dispenser and the outer pipe surrounding the inner pipe for containment of leaks therefrom, a dispenser having a shear valve at the bottom thereof for directing fuel into the dispenser, and a dispenser sump located beneath the dispenser, a dispenser sump connection system for preventing fuel leaks into the dispenser sump comprising: an inner flexible connector coupled between the inner pipe and the shear valve for completing the conveyance of fuel into the dispenser; an outer flexible connector coupled between the outer pipe and the shear valve enclosing the inner flexible connector and containing any fuel leaks therefrom; and means for maintaining a predetermined pressure within the interstitial space between the inner flexible connector and the outer flexible connector.
 2. The dispenser sump connection system of claim 1 wherein pressure maintaining means includes an orifice located at the upper end of the outer flexible connector.
 3. The dispenser sump connection system of claim 1 wherein the inner flexible connector is threadedly secured to an inner elbow joint fastened to the distal end of the inner pipe and an outer containment clamshell which is secured around the inner elbow joint.
 4. The dispenser sump connection system of claim 1 wherein the inner flexible connector is threadedly secured to the shear valve.
 5. The dispenser sump connection system of claim 1 further comprising: a first connection ring for coupling the outer flexible connector over the distal end of the inner pipe; a gasket seated between the first connection ring and the outer flexible connector for facilitating a pressure seal; and a clamping ring having a threaded locking device for securing and compressing the outer flexible connector and the first connection ring together.
 6. The dispenser sump connection system of claim 5 further comprising: a second connection ring for coupling the outer flexible connector to an outer housing of the shear valve; a gasket seated between the second connection ring and the outer flexible connector for facilitating a pressure seal; and a clamping ring having a threaded locking device for securing and compressing the outer flexible connector and the outer housing of the shear valve together. 